1. Field of the Invention
The present invention relates to a telephone set which is used by being connected to a telephone line.
2. Description of the Prior Art
FIG. 1 and FIG. 2 are respectively a perspective view and a plan view showing a telephone set according to the prior art. In the drawings, reference numeral 1 designates a telephone receiver, numeral 2 designates a telephone transmitter, numeral 3 designates push button switches, numeral 4 designates an indicator, numeral 5 designates a battery pack removably attached to the telephone body and numeral 6 designates an antenna stored in the telephone body.
Operation of the above-mentioned telephone set will now be explained. When the telescopic antenna 6 is fully pulled up, a desired telephone number is entered (keyed-in) by use of the push button switches 3, and a calling button is pressed, the telephone will be available for communication with the party being called. After that, communication can be conducted in the same manner as a conventional telephone. After the communication is over and a termination button is depressed, the telephone is initialized and ready for receiving another call. When the telephone is placed with the receiver and transmitter facing upwardly, no substantial problems will occur. However, when the telephone is placed on a horizontal plane during communication with the receiver and transmitter facing downwardly, as shown in FIG. 3, openings provided in the receiver and the transmitter face the same surface, and the signals being emitted from the receiver (such as sounds during communication) may be directed toward the transmitter, resulting in acoustic coupling.
Since the telephone set according to the prior art is constituted in this way, when the telephone is placed on a horizontal plane during communication with the transmitter and receiver facing downwardly, as shown in FIG. 3, openings or apertures provided at the respective positions of the transmitter and receiver face the same surface resulting in acoustic coupling between the transmitter and the receiver. When such acoustic coupling becomes substantial, it may appear as an echo distortion on the telephone line and thus the transmission performance or speech quality may be adversely affected.
FIG. 4 is a perspective view showing a handset which includes a transmitter and a receiver but which does not include operating buttons such as dial buttons, that is, the associated telephone set body includes such buttons and the handset is connected to the telephone set body with a cable. FIGS. 5(a) and (b) are a side elevation and a bottom view, respectively of the handset shown in FIG. 4 wherein numeral 11 denotes a receiver, numeral 12 denotes a transmitter, numeral 13 denotes an opening for the transmitter, and numeral 14 denotes slits which are provided for ornamental purposes and do not penetrate the housing of the handset. There are problems similar to those mentioned above in the handset of the type shown in FIGS. 4 and 5 also.